EPS calculation

I had superannuated from a Kolkata-based PSU on attaining 58 yrs age wef 31.03.2014. My joining date was on 01.06.1979. My erstwhile company defaulted in making eps contributions for the preceding 9 mths before my retirement and exit from eps. My basic plus da was well above Rs 6500 per mth at retirement and on 15.11.1995 my basic plus da was above Rs. 2500.00 per mth. After 2 and half years from my retirement, I have been awarded a pension of Rs. 1196.00 per mth. My colleagues who had retired earlier with less pay and similar service tenure receives pension above Rs.2000.00 pm. I cannot understand the basis of this low pension amt in my case. Shall be grateful if you could throw light on this issue and necessary action on my part.

Thank u very much for the informative post on EPS. A small clarification will equip me to take up my pension issue with RPFO. Will it be correct on my part to consider my Pensionable salary as : aggregate salary from April to June’13 ( for which contribution to EPS fund was made by my employer ) divided by 91 (days) and the resultant multiplied by 30 ( days) ie, ((3*6500)/91)*30= Rs,6429.00 Will be most obliged with ur confirmation.